1. Abstract The Methods Core of the LEAP Center will create a data platform that integrates information obtained at different levels of care of First Episode Psychosis (FEP) patients and will develop the computational tools that will allow Center investigators to access and analyze the integrated databases. Specifically, the Methods Core will provide the methodological expertise for the application of state-of-the-art machine leaning algorithms for clinical prediction, and for the application of cutting-edge causal inference techniques for comparative effectiveness research. First, the Methods Core will provide the database infrastructure to securely store, harmonize, link, manage, and analyze the high-dimensional databases that will be used by Center investigators. These databases include detailed clinical, demographic, socioeconomic information for each FEP patients, plus electronic health records and insurance claims, and longitudinal datasets on clinics characteristics and services offered. Many of these data sources have never been used for mental health research, either independently or in concert. We will create the only U.S.-based consortium approaching a thousand FEP patients. Second, the Methods Core will ensure that recent advances in clinical prediction and comparative effectiveness research can be applied to large databases of FEP patients and will be an incubator of methodological research in response to the requirements of the Center projects. It will serve as a platform for a synergistic collaboration between experts in several disciplines?psychiatry, statistics, epidemiology, and health policy?who will engage in high-impact studies to improve the clinical outcomes of FEP patients. Our project also provides a potential model for data consolidation and expertise sharing across multiple NIMH Alacrity P50 Centers. In summary, the Methods Core will support the data analysis activities throughout all projects, and will disseminate methodological advances amongst the community of mental health researchers and will therefore function as a national resource that facilitates the use of innovative methods beyond the Center investigators.